U.S. patent number 6,726,199 [Application Number 10/233,111] was granted by the patent office on 2004-04-27 for switchback device and switchback method.
This patent grant is currently assigned to Kabushiki Kaisha Toshiba. Invention is credited to Kunio Fukatsu, Atsushi Ina, Koji Kurokawa.
United States Patent |
6,726,199 |
Ina , et al. |
April 27, 2004 |
Switchback device and switchback method
Abstract
The switchback device has two switchback portions for inverting
the conveying path of paper-like materials and a detour conveying
path. The switchback portions receive paper-like materials in the
nip between the switchback rollers and the pinch rollers, clamp the
paper-like materials, decelerate, stop, and accelerate them in the
opposite direction in a clamping state, thereby switch back the
paper-like materials. The stopping time of paper-like materials in
the switchback portions is changed according to the length of the
paper-like materials in the conveying direction.
Inventors: |
Ina; Atsushi (Kanagawa-ken,
JP), Fukatsu; Kunio (Kanagawa-ken, JP),
Kurokawa; Koji (Kanagawa-ken, JP) |
Assignee: |
Kabushiki Kaisha Toshiba
(Tokyo, JP)
|
Family
ID: |
19112498 |
Appl.
No.: |
10/233,111 |
Filed: |
September 3, 2002 |
Foreign Application Priority Data
|
|
|
|
|
Sep 21, 2001 [JP] |
|
|
P2001-290113 |
|
Current U.S.
Class: |
271/65; 271/186;
271/291; 399/364 |
Current CPC
Class: |
B65H
15/012 (20200801); B65H 2511/11 (20130101); B65H
2404/1114 (20130101); B65H 2301/33312 (20130101); B65H
2513/50 (20130101); B65H 2511/11 (20130101); B65H
2220/01 (20130101); B65H 2513/50 (20130101); B65H
2220/02 (20130101) |
Current International
Class: |
B65H
15/00 (20060101); B65H 029/66 (); B65H 039/10 ();
B65H 029/00 () |
Field of
Search: |
;271/65,186,291
;399/364 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Walsh; Donald P.
Assistant Examiner: Bower; Kenneth W
Attorney, Agent or Firm: Pillsbury Winthrop LLP
Claims
What is claimed is:
1. A switchback device comprising: a conveying path to continuously
convey a plurality of paper-like materials; a switchback portion to
receive the paper-like material conveyed on the conveying path in a
nip, clamp the paper-like material, decelerate and stop the
paper-like material in the clamping state, then accelerate in an
opposite direction, send onto the conveying path, thereby invert a
conveying direction of the paper-like material; and a controller to
keep the paper-like material stopped in the switchback portion for
a time decided depending on a length of the paper-like material to
be conveyed to the switchback portion in the conveying direction
and control an inversion operation for the paper-like material by
the switchback portion so as to send out all paper-like materials
from the switchback portion at a same conveying pitch as that
before inversion.
2. The switchback device according to claim 1, further comprising:
a timing sensor to detect the paper-like material received in the
nip immediately before the nip; wherein the controller starts the
inversion operation for the paper-like material by the switchback
portion by taking detection of passing of a back end of the
paper-like material in the conveying direction via the timing
sensor as a trigger.
3. The switchback device according to claim 2, wherein a stopping
time of the paper-like material in the switchback portion is
decided so that a time required for detecting passing of an end of
the paper-like material in the conveying direction by the timing
sensor and sending the paper-like material from the switchback
portion is made equal for all paper-like materials.
4. A switchback device comprising: a conveying path to continuously
convey a plurality of paper-like materials; a switchback portion to
receive a paper-like material conveyed on the conveying path in a
nip, clamp the paper-like material, decelerate and stop the
paper-like material in the clamping state, then accelerate in an
opposite direction, send onto the conveying path, thereby invert a
conveying direction of the paper-like material; an upstream pitch
sensor to detect a conveying pitch between continuous two
paper-like materials conveyed to the switchback portion on the
conveying path; and a controller to control, when the conveying
pitch detected by the upstream pitch sensor is a short pitch which
is shorter than a preset reference pitch, so as to shorten a
processing time for a preceding paper-like material among the
continuous two paper-like materials by the switchback portion, an
inversion operation for the preceding paper-like material by the
switchback portion.
5. The switchback device according to claim 4, wherein the
controller, when the upstream pitch sensor detects the short pitch,
controls so as to shorten an acceleration time, a deceleration
time, and/or a stopping time for the preceding paper-like material
by the switchback portion.
6. The switchback device according to claim 4, wherein the
controller, when the upstream pitch sensor detects the short pitch,
changes a stop position of the preceding paper-like material so as
to shorten a conveying distance of the preceding paper-like
material in the switchback portion.
7. A switchback device comprising: a conveying path to continuously
conveying a plurality of paper-like materials; a switchback portion
to receive a paper-like material conveyed on the conveying path in
a nip, clamp the paper-like material, decelerate and stop the
paper-like material in the clamping state, then accelerate in an
opposite direction, send onto the conveying path, thereby invert a
conveying direction of the paper-like material; a detour conveying
path to detour the switchback portion; a downstream pitch sensor to
detect a conveying pitch between continuous two paper-like
materials conveyed on the conveying path after passing the
switchback portion or the detour conveying path; and a controller
to control the inversion operation by the switchback portion on the
basis of detection results by the downstream pitch sensor so that a
time required for the paper-like material to pass the switchback
portion and a time required for the paper-like material to pass the
detour conveying path are made equal.
8. The switchback device according to claim 7, wherein the
controller, on the basis of detection results by the downstream
pitch sensor, controls so as to shorten or extend an acceleration
time, a deceleration time, and/or a stopping time for the
paper-like materials in the switchback portion.
9. The switchback device according to claim 7, wherein the
controller, on the basis of detection results by the downstream
pitch sensor, changes a stop position of the paper-like materials
so as to shorten or extend a conveying distance of the paper-like
materials in the switchback portion.
10. A switchback device comprising: a conveying path to
continuously convey a plurality of paper-like materials; first and
second switchback portions to receive a paper-like material
conveyed on the conveying path in a nip, clamp the paper-like
material, decelerate and stop the paper-like material in the
clamping state, then accelerate in an opposite direction, send onto
the conveying path, thereby invert a conveying direction of the
paper-like material; a downstream pitch sensor to detect a convey
pitch between continuous two paper-like materials conveyed on the
conveying path after passing the first and second switchback
portions; and a controller to shorten or extend a processing time
for the paper-like material by at least one of the first and second
switchback portions and control the inversion operation by the
first and/or second switchback portion on the basis of detection
results by the downstream pitch sensor so that a time required for
the paper-like material to pass the first switchback portion and a
time required for the paper-like material to pass the second
switchback portion are made equal.
11. A switchback method comprising: continuously conveying a
plurality of paper-like materials along a conveying path; receiving
the paper-like material conveyed on the conveying path in a nip;
clamping the paper-like material in the nip; decelerating and
stopping the paper-like material in the clamping state;
accelerating the paper-like material in an opposite direction;
sending the paper-like material onto the conveying path, thereby
invert a conveying direction of the paper-like material; keeping
the paper-like material stopped for a time decided depending on a
length of the paper-like material to be conveyed in the conveying
direction; and controlling an inversion operation for the
paper-like material so as to send out all paper-like materials at a
same conveying pitch as that before inversion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority
from the prior Japanese Patent Application No. 2001-290113, filed
on Sep. 21, 2001: the entire contents of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a switchback device and switchback
method for inverting the conveying direction of a paper-like
material and inverting the top and bottom of the paper-like
material.
Conventionally, as a switchback device for inverting the conveying
direction of a paper-like material and inverting the top and bottom
of the paper-like material, a switchback device of a type of
allowing the end of a paper-like material in the conveying
direction to collide with a stopper, stopping the conveying of the
paper-like material once, sending the paper-like material with the
back end thereof positioned ahead in the opposite direction,
thereby inverting the conveying direction of the paper-like
material is known.
However, in a switchback device of this kind, a paper-like material
is stopped by letting the end thereof collide with a stopper, so
that a paper-like material comparatively unstiff is bent, thus a
jam may occur.
Further, when a switchback device of this kind is applied to a
device for continuously conveying a plurality of kinds of
paper-like materials different in the length in the conveying
direction in a coexisting state, even if the paper-like materials
are sent to the switchback device at a constant conveying pitch, a
problem arises that the conveying pitch of the paper-like materials
after inversion of the top and bottom is not always constant.
Furthermore, when a plurality of paper-like materials continuously
sent at a constant conveying pitch are to be continuously switched
back, if the conveying pitch between two paper-like materials to be
continuously sent is lower than the reference value, a problem
arises that the preceding paper-like material collides with the
succeeding paper-like material in the switchback device and a paper
jam occurs.
BRIEF SUMMARY OF THE INVENTION
The present invention is intended to provide a switchback device
and switchback method for inverting paper-like materials stably and
surely and keeping the conveying pitch between paper-like materials
after inversion constant.
According to the present invention, a switchback device is provided
and the device comprises a conveying path to continuously convey a
plurality of paper-like materials; a switchback portion to receive
the paper-like material conveyed on the conveying path in a nip,
clamping the paper-like material, decelerate and stop the
paper-like material in the clamping state, then accelerate in an
opposite direction, send onto the conveying path, thereby invert a
conveying direction of the paper-like material; and a controller to
keep the paper-like material stopped in the switchback portion for
a time decided depending on a length of the paper-like material to
be conveyed to the switchback portion in the conveying direction
and control an inversion operation for the paper-like material by
the switchback portion so as to send out all paper-like materials
from the switchback portion at a same conveying pitch as that
before inversion.
Further, according to the present invention, a switchback method is
provided and the method comprises continuously conveying a
plurality of paper-like materials along a conveying path; receiving
the paper-like material conveyed on the conveying path in a nip;
clamping the paper-like material in the nip; decelerating and
stopping the paper-like material in the clamping state;
accelerating the paper-like material in an opposite direction;
sending the paper-like material onto the conveying path, thereby
invert a conveying direction of the paper-like material; keeping
the paper-like material stopped for a time decided depending on a
length of the paper-like material to be conveyed in the conveying
direction; and controlling an inversion operation for the
paper-like material so as to send out all paper-like materials at a
same conveying pitch as that before inversion.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view showing a paper-like material processing
apparatus relating to the embodiment of the present invention;
FIG. 2 is a schematic view showing the structure of the switchback
device incorporated in the apparatus shown in FIG. 1;
FIG. 3 is a block diagram showing the control system for
controlling the operation by the switchback device shown in FIG.
2;
FIG. 4 is an operation illustration for illustrating the operation
by the switchback device shown in FIG. 2;
FIG. 5 is an operation illustration for illustrating the operation
by the switchback device shown in FIG. 2;
FIG. 6 is an operation illustration for explaining the operation by
the switchback device shown in FIG. 2;
FIG. 7 is an operation illustration for illustrating the operation
by the switchback device shown in FIG. 2;
FIG. 8 is an operation illustration for illustrating the operation
by the switchback device shown in FIG. 2;
FIG. 9 is an operation illustration for illustrating the operation
by the switchback device shown in FIG. 2;
FIG. 10 is a time chart for showing the processing time of the
inversion operation for paper-like materials different in
length;
FIG. 11 is a flow chart for explaining the processing operation
when a short pitch is generated; and
FIG. 12 is a flow chart for explaining the operation for monitoring
the conveying pitch after switching back and changing the control
parameter.
DETAILED DESCRIPTION OF THE INVENTION
The embodiment of the present invention will be explained in detail
hereunder with reference to the accompanying drawings.
FIG. 1 schematically shows the structure of a paper-like material
processing apparatus 1 relating to the embodiment of the present
invention. The paper-like material processing apparatus 1 inserts a
plurality of kinds of paper-like materials different in size in a
coexisting state into an insert port in a batch, arranges the
"front and back" and "top and bottom" of all paper-like materials
respectively in the same direction, and classifies and stacks them
for each kind.
The paper-like material processing apparatus 1 has a housing 2 in
an almost rectangular box shape which is an outer shell thereof. In
the stepped part on the upper right of the drawing of the housing
2, an insert port 3 where a plurality of paper-like materials C are
inserted in a batch in a state that they are stacked in the surface
direction and set in an upright state in the transverse direction
thereof is installed. The insert port 3 arranges all paper-like
materials C by making the lower end sides in the longitudinal
direction contact with the stage. In addition to this arrangement,
the insert port 3 moves a backup plate not shown in the drawing
along the stage in the surface direction of the paper-like
materials C and presses the paper-like material C at the left end
of the drawing on the stage against a pair of take-out rollers 4.
When the pair of rollers 4 rotate, the paper-like materials C on
the stage are sequentially taken out starting from the one at the
left end from the lower end side thereof onto a conveying path
5.
On the conveying path 5 in the neighborhood of the insert port 3, a
posture correction device 6 is installed. The posture correction
device 6 corrects a defective posture of a paper-like material C in
each processing portion installed on the conveying path 5 on the
downstream side of the posture correction device 6. Namely, to
prevent a defect due to a skew or a shift, the posture correction
device 6 corrects a skew and a shift of each paper-like material C.
In this embodiment, the posture correction device 6 corrects the
conveying posture of each paper-like material C so that the center
of the paper-like material C taken out in the transverse direction
is positioned on the central line of the conveying path 5 and the
longer end side of the paper-like material C in the longitudinal
direction is orthogonal to the central line.
On the conveying path 5 in the neighborhood of the posture
correction device 6, a detecting device 7 for detecting
characteristics such as the kind of each paper-like material C,
size, directions of the "front and back" and "top and bottom", and
existence of soil or damage is installed. The detecting device 7
reads various types of information from the surface of each
paper-like material C conveyed on the conveying path 5, carries out
logic operations for the read information and compares it with the
standard information, and detects the aforementioned
characteristics of each paper-like material C.
On the conveying path 5 on the downstream side of the detecting
device 7, a plurality of gates G1 to G9 for selectively switching
the conveying direction of each paper-like material C on the basis
of the detection results of the detecting device 7 are
installed.
On one conveying path branched at the position of the gate G1
installed on the uppermost stream side, a switchback device 10
relating to the embodiment of the present invention is installed.
The switchback device 10 functions so as to invert the conveying
direction of each paper-like material C conveyed via the gate G1,
invert the top and bottom, and send it onto the conveying path
again.
The other conveying path branched at the position of the gate G1
functions as a detour conveying path 8 for detouring the switchback
device 10. The detour conveying path 8 is preset in such a length
that a paper-like material C passing the switchback device 10 via
the gate G1 and a paper-like material C passing the detour
conveying path 8 reach a joining portion 9 at the same time
interval.
The detour conveying path 8 is branched to a rejection root path 11
on the way to the joining portion 9 and the gate 2 is installed at
this branch position. At the terminal of the rejection root path 11
branched via the gate G2, a rejection box 12 for receiving a
paper-like material C to be rejected is installed. The paper-like
material C to be rejected is a paper-like material decided as the
process at the latter stage being impossible such as paper-like
materials which are decided as double feed by the detecting device
7, a paper-like material decided as greatly skewed beyond a
predetermined level, or a paper-like material severely damaged.
Further, a paper-like material whose characteristics cannot be
detected by the detecting device 7 is also received into the
rejecting box 12. The rejecting box 12 is arranged above the insert
port 3 and can be accessed from outside the housing 2.
The conveying path 5 on the downstream side of the joining portion
9 is branched in two directions again and the gate G3 is installed
at the position of the branch. On one conveying path branched at
the position of the gate G3, a front/back reversing mechanism 13 as
indicated in U.S. Pat. No. 4,629,382 (Dec. 16, 1986) is installed.
The front/back reversing mechanism 13 has a twist conveying path
twisted at 180.degree. round the central axis from the inlet
thereof to the outlet. And, when a paper-like material C passes the
twist conveying path, the front and back of the paper-like material
C is inverted.
The other conveying path branched at the position of the gate G3
functions as a detour conveying path 14 for detouring the
front/back reversing mechanism 13. The detour conveying path 14 is
preset in such a length that a paper-like material C passing the
front/back reversing mechanism 13 via the gate G3 and a paper-like
material C passing the detour conveying path 14 reach a joining
portion 15 at the same time interval.
One conveying path branched in two directions at the position of
the gate G4 on the downstream side of the joining portion 15
functions as a horizontal conveying path 16 extending almost
horizontally in the right direction of the drawing. On the
horizontal conveying path 16, the remaining five gates G5 to G9 are
installed at almost equal intervals. At the positions branched
respectively by the gates G5, G6, G7, G8, and G9 below the
horizontal conveying path 16, six stackers 17a to 17f larger than
the number of gates by one are installed.
The paper-like materials C passing the joining portion 15
selectively pass the switchback device 10 and/or the front/back
reversing mechanism 13 and the directions of the "front and back"
and "top and bottom" are arranged in a fixed direction
respectively. Therefore, paper-like materials C stacked in the
respective stackers 17a to 17f are arranged in the "front and back"
and "top and bottom" and respectively stacked in predetermined
stackers for each kind.
Further, the other conveying path branched at the position of the
gate G4 is derived outside the housing 2 of the processing
apparatus 1 and connected to an external device not shown in the
drawing.
Next, the switchback device 10 will be explained in detail by
referring to FIG. 2.
The switchback device 10 has a gate 21 for selectively pointing
paper-like materials C conveyed via the gate G1 to two switchback
portions 20R and 20L (first and second switchback portions)
installed symmetrically right and left with respect to the
conveying path 5. Namely, the paper-like materials C conveyed to
the switchback device 10 are alternately sent to the left and right
switchback portions 20R and 20L by switching the gate 21 between
the two positions. Further, the two switchback portions 20R and 20L
have almost the same structure and function, so that here the
switchback portion 20R installed on the right of the conveying path
5 will be explained representatively. Therefore, with respect to
the switchback portion 20L on the left, the same numerals (L is
added at the end of each numeral) are respectively assigned to the
members functioning in the same way and detailed explanation will
be omitted.
The switchback portion 20R has a tapping wheel 22R for guiding the
end of a paper-like material C conveyed via the gate 21 in the
conveying direction into the switchback portion 20R, two switchback
rollers 23R installed in parallel on one side of the paper-like
material C guided via the tapping wheel 22R, two pinch rollers 24R
pressed against each roller 23R so as to clamp the paper-like
material C between the switchback rollers 23R and themselves, and a
motor 25R for rotating the two switchback rollers 23R in the
forward and backward directions. Further, on the conveying path of
paper-like materials C passing the switchback portion 20R, a
plurality of guide members for guiding the paper-like materials C
are installed.
FIG. 3 shows a block diagram of the control system for controlling
the operation of the switchback device 10. To the controller 30 for
controlling the operation of the switchback device 10, a solenoid
31 for driving six shift sensors SC3, SC4R, SC4L, SC5R, SC5L, and
SC6 for monitoring paper-like materials passing the switchback
device 10 and the gate 21, a motor 32 for rotating the tapping
wheels 22R and 22L installed respectively in the left and right
switchback portions 20R and 20L, a motor controller 33 for driving
the motors 25R and 25L for rotating the switchback rollers 23R and
23L in the forward and backward directions, a timer 34 for
measuring the passing time of paper-like materials C through the
shift sensors SC3 and SC6 so as to detect the conveying pitch
thereof and measuring the stopping time thereof in the switchback
portions 20R and 20L, and a memory 35 storing the operation program
of the switchback device 10, the aforementioned stopping time
according to the length of each paper-like material C in the
conveying direction, and the deceleration time, acceleration time,
and stopping time of paper-like materials C according to the
aforementioned measured conveying pitch beforehand are
connected.
As shown in FIG. 2, the shift sensor SC1 is installed on the
conveying path 5 on the upstream side of the gate G1 in the
conveying direction. The shift sensor SC2 is installed on the
detour conveying path 8 immediately behind the gate G1. The shift
sensor SC3 is installed on the conveying path 5 reaching the gate
21 from the gate G1. The shift sensor SC4R is installed at the
position for detecting paper-like materials moving from the gate 21
to the switchback portion 20R on the right. The shift sensor SC5R
is installed at the position for detecting paper-like materials
guided to the switchback portion 20R on the right. The shift sensor
SC6 is installed on the conveying path 5 immediately behind the
joining portion 9. The shift sensor SC3 functions as an upstream
pitch sensor of the present invention, and the shift sensor SC4R
functions as a timing sensor of the present invention, and the
shift sensor SC6 functions as a downstream side pitch sensor of the
present invention.
Next, the processing operation by the switchback device 10
structured as mentioned above will be explained by referring to
FIGS. 2 to 10.
Firstly, as shown in FIG. 2, in timing with passing of a paper-like
material C conveyed via the conveying path 5 from the left of the
drawing through the shift sensor SC1, the gate G1 is switched. The
gate G1, when the paper-like material C is a paper-like material to
be switched back, is switched to the position shown by a dashed
line in FIG. 2 so as to guide the paper-like material C to the
switchback device 10 and when it is judged that the paper-like
material C is a paper-like material not to be switched back or the
paper-like material C is a paper-like material which cannot be
reused, the gate G1 is switched to the position (shown by a solid
line in FIG. 2) for guiding the paper-like material C to the detour
conveying path 8.
And, the gate G2 is switched in timing with passing of the
paper-like material C guided to the detour conveying path 8 via the
gate G1 through the shift sensor SC2. The gate G2, when the
paper-like material C is a paper-like material which cannot be
reused, is switched to the position (shown by a solid line in FIG.
2) for guiding the paper-like material C to the rejection root path
11 and when the paper-like material C is a paper-like material
other than it, the gate G2 is switched to the position (shown by a
dashed line in FIG. 2) for guiding the paper-like material C to the
joining portion 9.
Further, in timing with passing of the end of the paper-like
material C guided to the switchback device 10 via the gate G1 in
the conveying direction through the shift sensor SC3, the gate 21
is switched. The gate 21 is switched so as to distribute the
paper-like material C led to the switchback device 10 alternately
to the left and right switchback portions 20R and 20L.
For example, when the gate 21 is switched to the position shown by
a solid line in FIG. 2, the paper-like material C is led to the
switchback portion 20R on the right. The paper-like material C
guided to the switchback portion 20R, as shown in FIG. 4, is
detected passing of the end thereof in the conveying direction by
the shift sensor SC4R, then guided by the tapping wheel 22R, and
led to the nip between the paired rollers 23R and 24R. The
paper-like material C received in the nip is clamped by the two
nips between the two switchback rollers 23R and the two pinch
rollers 24R and received in the switchback portion 20R in this
state by the switchback rollers 23R rotating in the direction of
the arrow (the forward direction) shown in the drawing.
And, as shown in FIG. 5, taking the detection of the back end of
the paper-like material C in the conveying direction by the shift
sensor SC4R as a trigger, the inversion operation for the
paper-like material C is started by the switchback rollers 23R. By
this inversion operation, the two switchback rollers 23R are
sequentially decelerated and stopped (the state shown in FIG. 6)
and inverted as shown in FIG. 7 after a lapse of a predetermined
stopping time and the paper-like material C is accelerated in the
opposite direction and sent from the switchback portion 20R. At
this time, the end of the paper-like material C, inverted in the
conveying direction, in the conveying direction is guided by the
tapping wheel 22R as shown in FIG. 7 and the paper-like material C
is led onto the conveying path via the joining portion 9.
At this time, taking the detection of the back end of the inverted
paper-like material C in the conveying direction by the shift
sensor SC5R installed in the switchback portion 20R as a trigger,
the inverted switchback rollers 23R are decelerated and stopped.
This state is shown in FIG. 8. And, after the paper-like material C
after switching back is sent from the switchback portion 20R, as
shown in FIG. 9, the switchback rollers 23R are accelerated in the
forward direction and set up for receiving the next paper-like
material C.
In this embodiment, during the inversion operation, the stopping
time of the paper-like material C in the switchback portion 20R is
changed depending on the length of the paper-like material C in the
conveying direction. The length of the paper-like material C in the
conveying direction is detected by the detecting device 7
beforehand or the time required for the paper-like material C to
pass the plurality of shift sensors SC1, SC3, and SC4R installed on
the conveying path extending to the switchback portion 20R is
calculated.
Namely, the stopping time of the paper-like material C in the
switchback portion 20R is preset according to the length of the
paper-like material C so that the time required for detecting the
end of the paper-like material C in the conveying direction by the
shift sensor SC4R, switching back the paper-like material by the
inversion operation, and then sending it from the switchback
portion 20R, for example, the time required for the end of the
paper-like material C in the conveying direction to reach the shift
sensor SC6 is made equal for all paper-like materials C sent to the
switchback device 10. In short, a comparatively short paper-like
material is stopped for a comparatively long time and a
comparatively long paper-like material is stopped for a
comparatively short time. The stopping time preset according to the
length of paper-like materials is stored in the memory 35
beforehand.
Namely, the controller 30 of the switchback device 10 obtains
information concerning the length of the paper-like material C from
the detecting device 7, reads the stopping time according to the
length from the memory 35, and controls the inversion operation by
the switchback rollers 23R so as to keep the paper-like material C
stopped in the switchback portion 20R for this stopping time.
For example, as shown in FIG. 10, when the aforementioned stop
control of the present invention is applied to two paper-like
materials A and B different in length, the times required for the
ends of the paper-like materials A and B to pass from the shift
sensor SC4R to the shift sensor SC6 are the same.
Namely, with respect to the comparatively long paper-like material
A, the time required for the shift sensor SC4R to detect from
passing of the end thereof to passing of the back end thereof is
comparatively long. On the other hand, the time required for the
comparatively short paper-like material B to pass the shift sensor
SC4R is comparatively short. Namely, the paper-like material B is
earlier in the timing of starting the inversion operation than the
paper-like material A. And, in a state of such a time difference,
taking the passing of the back ends of the paper-like materials C
through the shift sensor S4R as a trigger, the aforementioned
inversion operation is started. In the inversion operation, by the
switchback rollers 23R rotating in the forward direction after a
predetermined time lag, the paper-like materials A and B are
decelerated. The time lag and deceleration time are the same in the
paper-like materials A and B. Here, the stopping time of the
paper-like material A is made shorter than the stopping time of the
paper-like material B by the aforementioned time difference. The
stopping time, as mentioned above, is preset according to the
length of the paper-like material and controlled by the controller
30. By doing this, the aforementioned time difference is offset. In
a state that the time difference is offset in this way, the
switchback rollers 23R are inverted and accelerated for the same
time and the paper-like materials A and B are sent from the
switchback portion 20R in the same timing.
When the processing time from sending of the paper-like material C
to the switchback portion 20R to sending out from the switchback
portion 20R, as mentioned above, is made equal for all paper-like
materials C instead of deciding according to the length of the
paper-like materials C, the conveying pitch of a plurality of
paper-like materials C to be continuously sent to the switchback
portion 20R can be made equal before and after switching back and
the sending timing can be adjusted.
Next, the processing operation when a short pitch is caused in
paper-like materials C to be sent to the switchback device 10 will
be explained by referring to the flow chart shown in FIG. 11. Short
pitch is referred to as a state that the conveying pitch P between
two paper-like materials to be continuously conveyed is shorter
than a preset reference pitch PO and it is highly probable that the
two paper-like materials having a short pitch collide with each
other in the switchback portion and cause a jam.
As shown in FIG. 11, firstly, among two paper-like materials C
continuously sent to the switchback device 10 via the gate G1, the
back end of the preceding paper-like material C1 in the conveying
direction and the end of the succeeding paper-like material C2 in
the conveying direction are detected via the shift sensor SC3. And,
by the controller 30, the conveying pitch P between the two
paper-like materials is calculated from the difference between the
passing times and the conveying speed (Step S1).
And, the conveying pitch P is compared with the preset reference
pitch PO (Step S2). As a comparison result, when it is judged that
the conveying pitch P is equal to or higher than the reference
pitch PO (Step S2, NO), the two paper-like materials C1 and C2 are
switched back as usual (Step 4).
On the other hand, as a result of judgment at Step S2, when it is
judged that the conveying pitch P is lower than the reference pitch
PO (Step S2, YES), the control parameter for the preceding
paper-like material C1 is changed so as to shorten the processing
time required for the inversion operation for the paper-like
material C1 (Step S3). The control parameter is changed, for
example, so as to shorten the acceleration time, deceleration time,
and/or the stopping time of the motor 25R for rotating the
switchback rollers 23R. Or, the control parameter is changed so as
to shorten the conveying distance during the inversion operation of
the paper-like material C1, concretely, to bring the stop position
of the paper-like material C1 close to the tapping wheel 22R.
As mentioned above, a short pitch is detected on the conveying path
on the upstream side of the switchback device 10, and among
paper-like materials having a short pitch, the control parameter
for the preceding paper-like material C1 is changed, and the
preceding paper-like material C is earlier sent from the switchback
portion, thus even paper-like materials in a short pitch state can
be continuously switched back surely and stably.
Meanwhile, in the aforementioned embodiment, the length of the
detour conveying path 8 for detouring the switchback device 10 is
set so that paper-like materials C passing the switchback device 10
and paper-like materials C passing the detour conveying path 8
reach the joining portion 9 at the same time interval, so that
regardless of existing of switching back, all paper-like materials
C can reach the joining portion 9 in the same sequence and at the
same pitch. However, the time required for paper-like materials C
to pass the switchback device 10 and the time required to pass the
detour conveying path 8 may be changed with time even if the
conveying path lengths are made equal.
For example, in the switchback device 10, it is known that due to
friction and soil with time between the switchback rollers 23R and
23L and the pinch rollers 24R and 24L, the clamping force for
paper-like materials C is weakened with time. When the clamping
force becomes weaker, the conveying speed for paper-like materials
C is reduced and the time required to pass the switchback device 10
becomes longer.
Further, when the driving force for letting paper-like materials C
pass the detour conveying path 8 is supplied to units other than
the switchback device 10 in common, if the driving force becomes
weaker due to load changes in the whole paper-like material
processing apparatus 1, the conveying speed for paper-like
materials passing the detour conveying path 8 is reduced and the
passing time through the detour conveying path 8 becomes
longer.
When the time required for paper-like materials C to pass the
switchback device 10 and the time required for paper-like materials
C to pass the detour conveying path 8 are changed with time like
this, even if the switchback device is operated as mentioned above,
the conveying pitch between paper-like materials C passing the
joining portion 9 is not fixed. Therefore, in this embodiment, the
conveying pitch of paper-like materials C passing the joining
portion 9 is monitored by the shift sensor SC6, and the time
difference between the time required to pass the switchback device
10 and the time required to pass the detour conveying path 8 is
detected, and the control parameter of the switchback device 10 is
periodically changed so as to eliminate the time difference
Next, by referring to the flow chart shown in FIG. 12, the changing
method for the control parameter for offsetting the change of the
passing time with time will be explained.
Firstly, the conveying pitch of a plurality of paper-like materials
C passing the switchback device or the detour conveying path 8 is
continuously detected for a preset optional number of paper-like
materials via the shift sensor SC6 (Step S5). Detection results are
classified for each path of continuous two paper-like materials C
and stored in the memory 35 (Step S6).
Concretely, the conveying pitch of a combination of, among
continuous two paper-like materials C, passing of the preceding
paper-like material C1 through the detour conveying path 8 and
passing of the succeeding paper-like material C2 also through the
detour conveying path 8 is assumed as P1, and the conveying pitch
of a combination of passing of the preceding paper-like material C1
through the detour conveying path 8 and passing of the succeeding
paper-like material C2 through the switchback device 10 is assumed
as P2, and the conveying pitch of a combination of passing of the
preceding paper-like material C1 through the switchback device 10
and passing of the succeeding paper-like material C2 through the
detour conveying path 8 is assumed as P3.
And, mean values P1m, P2m, and P3m of P1, P2, and P3 which are
classified and recorded in the memory 35 under the condition that
the detection count of conveying pitches reaches the preset number
N (Step S7, YES) are calculated (Step S8). Thereafter, these mean
values P1m, P2m, and P3m are compared and the control parameter of
the switchback device 10 is changed.
For example, when the relation of P2m<P1m<P3m is held (Step
S9, YES), it can be judged that the time required for the
paper-like materials C to pass the switchback device 10 is shorter
than the time required for the paper-like materials C to pass the
detour conveying path 8. In this case, the control parameter is
changed so that the passing time through the switchback device 10
is made longer (Step S10). Concretely, the control parameter of the
switchback device 10 is changed so as to make the acceleration
time, deceleration time, and/or stopping time of the motor 25R for
rotating the switchback rollers 23R longer. Or, so as to make the
conveying distance during the inversion operation of paper-like
materials C longer, that is, so as to keep the stop position of
paper-like materials C away from the tapping wheel 22, the control
parameter is changed.
When the relation of P1m<P2m is held and the relation of
P1m>P3m is held (Step S11, YES), it can be judged that the time
required for the paper-like materials C to pass the switchback
device 10 is longer than the time required for the paper-like
materials C to pass the detour conveying path 8. In this case, the
control parameter is changed so that the passing time through the
switchback device 10 is made shorter (Step S12). Concretely, the
control parameter of the switchback device 10 is changed so as to
make the acceleration time, deceleration time, and/or stopping time
of the motor 25R for rotating the switchback rollers 23R shorter.
Or, so as to make the conveying distance during the inversion
operation of paper-like materials C shorter, that is, so as to
bring the stop position of paper-like materials C close to the
tapping wheel 22, the control parameter is changed.
On the other hands, when the aforementioned relations of Steps S9
and S10 are not held (Step S9, NO and Step S11, NO), it can be
judged that there is little time difference between the time
required to pass the switchback device 10 and the time required to
pass the detour conveying path 8. In this case, the control
parameter of the switchback device 10 is not changed (Step
S13).
When the conveying pitch of paper-like materials C passing the
joining portion 9 is monitored as mentioned above, even if the
passing time of paper-like materials C passing the switchback
device 10 and/or the detour conveying path 8 is changed with time,
the conveying pitch of paper-like materials C after switching back
can be kept constant. By doing this, a higher reliable switchback
operation can be realized.
Further, the present invention is not limited to the aforementioned
embodiment and can be deformed variously within the scope of the
present invention. For example, in the aforementioned embodiment,
the classified and recorded conveying pitches are averaged and
compared. However, in addition to it, changes of the passing time
with time may be obtained using a statistical means such as the
normal distribution.
Further, in the aforementioned embodiment, the passing time of
paper-like materials C passing the switchback device 10 and the
passing time of paper-like materials C passing the detour conveying
path 8 are compared and the control parameter of the switchback
device 10 is changed. However, when the switchback device 10 has
two switchback portions 20R and 20L like this embodiment, the
control parameter may be changed by comparing the passing times
required for the paper-like materials C to pass the switchback
portions 20R and 20L.
As explained above, the switchback device of the present invention
has such a constitution and an operation as mentioned above, so
that paper-like materials can be turned upside down stably and
surely and the conveying pitch between paper-like materials after
turning upside down can be kept constant.
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